Importance

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Abstract

An electromechanical control for use with a joystick lever which swivels along x and y axes simultaneously. The control has a light source and two light sensitive phototransistors. The light source emits a beam which is split into two parts. A light control sector is pivoted on the base, and mechanically linked to the lever. The sector is disposed in the paths of the two parts of the split beam, and has two arcuate translucent portions, each translucent portion being on its own radius and the portions having a common center. One part of the beam passes through one translucent portion and the other part of the beam passes through the second. The phototransistors are disposed on that side of the translucent portions opposite the location of the light source. The one translucent portion has a graduated opacity along its length, such that the light arriving at one phototransistor varies as the sector pivots by movement of the lever. The other translucent portion has a substantially monotonous or constant opacity, such that the beam part passing therethrough does not vary with movement of the lever. The arrangement is such that only when the lever is in its exact center position with respect to the base, is the opacity of the one translucent portion at the location of its phototransistor the same as that of the uniform opacity of the other translucent portion, whereby a precise indication of the said center position can be obtained by measurement of the relative outputs of the phototransistors.

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First Claim